1. Field of the Invention
The present invention relates to a cleaning apparatus and method for removing colorant adhered to a surface, and more particularly to a cleaning apparatus and method that is adapted to separately collect the differently colored colorants that are removed from the surface with a minimum of cross-contamination of the collected colorants.
2. Description of the Prior Art
Electrophotography has enjoyed rapid growth as a convenient and efficient means for reproducing original documents. Most electrophotographic copiers produce black and white reproductions. These copiers, in general, operate by reproducing an electrostatic image of the document onto a charged photoconductor and developing this image at a developer station by dusting onto the photoconductor electroscopic opaque charged particles such as toner particles.
The toner particles selectively adhere to the charged areas in accordance with the electrostatic image and later these particles are transferred to a receiver sheet such as a sheet of paper, in the case of a plain-paper copier, to reproduce onto the paper the image of the original document. The particles are then fused onto the paper to provide a permanent copy of the original. While these copiers work well, there is a residue of particles which do not transfer to the paper and remain on the photoconductor. Most of these particles must be removed prior to the next copy cycle to ensure the quality of the next copy. To this end, cleaning apparatus such as brushes or skiving blades are provided for removing the particles and a vacuum may be provided for collecting the particles removed. Efficiency of the copier is enhanced and per copy cost reduced by recirculating these used toner particles back to the developer station for subsequent use.
Electrophotographic copiers producing multicolor copies are also known. In general, these employ a photoconductor, such as a drum or belt, upon which color separation images of the document to be reproduced are formed sequentially through different filters. Each image is developed on the photoconductor with a colorant such as an appropriate color toner and the toner image is then transferred to a receiver sheet. The sheet is recirculated in timed relation with the developed images on the photoconductor so that each color transfers accurately in superimposed register onto the sheet to form the multicolor copy. Before each image area on the photoconductor is returned to the exposure station for a subsequent exposure such as for reproduction of a different color image or a next copy cycle, residual toner particles remaining on the photoconductor are removed by a brush or other cleaning device. Most cleaning apparatus, particularly those incorporated in color copiers using dry toner particles, have in the past merely collected the residual toner particles for disposal. In U.S. Pat. No. 3,910,232, an apparatus is described for collecting colored developer particles and using intermingled colors as black or further mixing them with black developer particles for use as a black developer material. Since color toners for use in a multicolor electrophotographic processes are in general more expensive than black toners, it would be more desirable to recirculate collected residual toner particles to their original developer supplies rather than commingle them to produce a less valued product.
In U.S. Pat. Nos. 3,900,003 and 3,910,231, polychromatic electrophotographic copiers are described each of which include a developer station that causes differently colored liquid developers to be sequentially applied to a photoconductor. Excess liquid developer of each color flows onto a belt or roller. This excess developer is removed by skiving blades, each of which are associated with a respective color. Each of the blades is actuated in turn to remove its respective color developer. The differently colored liquid developers are collected and may be recirculated back to their respective developer supply tanks. While this may work well for removing liquid developers, the use of dry toner particles or colorants presents problems.
With the use of dry toner particles in copiers, there is a tendency for these particles to become entrained in air currents established by the moving parts of the machine. A problem is therefore presented of finding an efficient process and means for removing of colored particles from a surface and for collecting these particles by their respective colors with a minimum of contamination by airborne particles of other colors.